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Merged
shamardy merged 4 commits into from
Feb 5, 2026
Merged

feat(v1): add SafeERC20 support for USDT compatibility #11

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eb10f9e
feat(v1): add SafeERC20 support for USDT compatibility
shamardy Jan 30, 2026
d2974f1
refactor(v1): remove NFT code, keep minimal ETH/ERC20 with SafeERC20
shamardy Jan 30, 2026
cb6fd6f
chore(deps): update OpenZeppelin to 5.4.0, reorganize dependencies
shamardy Jan 30, 2026
1ff56f7
feat(v1): add CREATE2 deployment infra and deploy to Ethereum mainnet
shamardy Feb 4, 2026
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294 changes: 11 additions & 283 deletions contracts/EtomicSwap.sol
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Original file line number Diff line number Diff line change
@@ -1,14 +1,12 @@
// SPDX-License-Identifier: MIT

pragma solidity ^0.8.30;
pragma solidity ^0.8.33;
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC721/IERC721.sol";
import "@openzeppelin/contracts/token/ERC721/IERC721Receiver.sol";
import "@openzeppelin/contracts/token/ERC1155/IERC1155.sol";
import "@openzeppelin/contracts/token/ERC1155/IERC1155Receiver.sol";
import "@openzeppelin/contracts/utils/introspection/ERC165.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";

contract EtomicSwap {
using SafeERC20 for IERC20;

contract EtomicSwap is ERC165, IERC1155Receiver, IERC721Receiver {
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@mariocynicys mariocynicys Jan 30, 2026

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maybe we better keep erc165?

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@shamardy shamardy Feb 3, 2026

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ERC165 is for interface detection - lets other contracts query "do you support interface X?".

We had it because the old contract implemented IERC721Receiver/IERC1155Receiver for NFT support. Standard ERC20 doesn't require ERC165 (it predates it), and ERC721/ERC1155 are the ones that mandate it for their receiver callbacks.

With NFTs removed, there's no interface to advertise. Our contract uses safeTransferFrom to pull tokens (not receive via callback), so no receiver interface is needed.

enum PaymentState {
Uninitialized,
PaymentSent,
Expand Down Expand Up @@ -65,8 +63,9 @@ contract EtomicSwap is ERC165, IERC1155Receiver, IERC721Receiver {
address receiver,
bytes20 secretHash,
uint64 lockTime
) external payable {
) external {
require(receiver != address(0), "Receiver cannot be the zero address");
require(tokenAddress != address(0), "Token address cannot be zero");
require(amount > 0, "Payment amount must be greater than 0");
require(
payments[id].state == PaymentState.Uninitialized,
Expand All @@ -89,12 +88,7 @@ contract EtomicSwap is ERC165, IERC1155Receiver, IERC721Receiver {
emit PaymentSent(id);

// Now performing the external interaction
IERC20 token = IERC20(tokenAddress);
// Ensure that the token transfer from the sender to the contract is successful
require(
token.transferFrom(msg.sender, address(this), amount),
"ERC20 transfer failed: Insufficient balance or allowance"
);
IERC20(tokenAddress).safeTransferFrom(msg.sender, address(this), amount);
}

function receiverSpend(
Expand Down Expand Up @@ -130,90 +124,10 @@ contract EtomicSwap is ERC165, IERC1155Receiver, IERC721Receiver {
if (tokenAddress == address(0)) {
payable(msg.sender).transfer(amount);
} else {
IERC20 token = IERC20(tokenAddress);
require(
token.transfer(msg.sender, amount),
"ERC20 transfer failed: Contract may lack balance or token transfer was rejected"
);
IERC20(tokenAddress).safeTransfer(msg.sender, amount);
}
}

function receiverSpendErc721(
bytes32 id,
bytes32 secret,
address tokenAddress,
uint256 tokenId,
address sender
) external {
// Check if the payment state is PaymentSent
require(
payments[id].state == PaymentState.PaymentSent,
"Invalid payment state. Must be PaymentSent"
);
// Check if the function caller is an externally owned account (EOA)
require(msg.sender == tx.origin, "Caller must be an EOA");

bytes20 paymentHash = ripemd160(
abi.encodePacked(
msg.sender,
sender,
ripemd160(abi.encodePacked(sha256(abi.encodePacked(secret)))),
tokenAddress,
tokenId
)
);
require(paymentHash == payments[id].paymentHash, "Invalid paymentHash");

// Effects
payments[id].state = PaymentState.ReceiverSpent;

// Event Emission
emit ReceiverSpent(id, secret);

// Interactions
IERC721 token = IERC721(tokenAddress);
token.safeTransferFrom(address(this), msg.sender, tokenId);
}

function receiverSpendErc1155(
bytes32 id,
uint256 amount,
bytes32 secret,
address tokenAddress,
uint256 tokenId,
address sender
) external {
// Check if the payment state is PaymentSent
require(
payments[id].state == PaymentState.PaymentSent,
"Invalid payment state. Must be PaymentSent"
);
// Check if the function caller is an externally owned account (EOA)
require(msg.sender == tx.origin, "Caller must be an EOA");

bytes20 paymentHash = ripemd160(
abi.encodePacked(
msg.sender,
sender,
ripemd160(abi.encodePacked(sha256(abi.encodePacked(secret)))),
tokenAddress,
tokenId,
amount
)
);
require(paymentHash == payments[id].paymentHash, "Invalid paymentHash");

// Effects
payments[id].state = PaymentState.ReceiverSpent;

// Event Emission
emit ReceiverSpent(id, secret);

// Interactions
IERC1155 token = IERC1155(tokenAddress);
token.safeTransferFrom(address(this), msg.sender, tokenId, amount, "");
}

function senderRefund(
bytes32 id,
uint256 amount,
Expand All @@ -225,6 +139,7 @@ contract EtomicSwap is ERC165, IERC1155Receiver, IERC721Receiver {
payments[id].state == PaymentState.PaymentSent,
"Invalid payment state. Must be PaymentSent"
);

bytes20 paymentHash = ripemd160(
abi.encodePacked(
receiver,
Expand All @@ -247,194 +162,7 @@ contract EtomicSwap is ERC165, IERC1155Receiver, IERC721Receiver {
if (tokenAddress == address(0)) {
payable(msg.sender).transfer(amount);
} else {
IERC20 token = IERC20(tokenAddress);
require(token.transfer(msg.sender, amount));
}
}

function senderRefundErc721(
bytes32 id,
bytes20 secretHash,
address tokenAddress,
uint256 tokenId,
address receiver
) external {
require(
payments[id].state == PaymentState.PaymentSent,
"Invalid payment state. Must be PaymentSent"
);
bytes20 paymentHash = ripemd160(
abi.encodePacked(
receiver,
msg.sender,
secretHash,
tokenAddress,
tokenId
)
);
require(paymentHash == payments[id].paymentHash, "Invalid paymentHash");
require(
block.timestamp >= payments[id].lockTime,
"Current timestamp didn't exceed payment lock time"
);

payments[id].state = PaymentState.SenderRefunded;

emit SenderRefunded(id);

IERC721 token = IERC721(tokenAddress);
token.safeTransferFrom(address(this), msg.sender, tokenId);
}

function senderRefundErc1155(
bytes32 id,
uint256 amount,
bytes20 secretHash,
address tokenAddress,
uint256 tokenId,
address receiver
) external {
require(
payments[id].state == PaymentState.PaymentSent,
"Invalid payment state. Must be PaymentSent"
);
bytes20 paymentHash = ripemd160(
abi.encodePacked(
receiver,
msg.sender,
secretHash,
tokenAddress,
tokenId,
amount
)
);
require(paymentHash == payments[id].paymentHash, "Invalid paymentHash");
require(
block.timestamp >= payments[id].lockTime,
"Current timestamp didn't exceed payment lock time"
);

payments[id].state = PaymentState.SenderRefunded;

emit SenderRefunded(id);

IERC1155 token = IERC1155(tokenAddress);
token.safeTransferFrom(address(this), msg.sender, tokenId, amount, "");
}

function onERC1155Received(
address operator,
address from,
uint256 tokenId,
uint256 value,
bytes calldata data
) external override returns (bytes4) {
// Decode the data to extract HTLC parameters
(
bytes32 id,
address receiver,
address tokenAddress,
bytes20 secretHash,
uint64 lockTime
) = abi.decode(data, (bytes32, address, address, bytes20, uint64));

require(receiver != address(0), "Receiver must not be zero address");
require(tokenAddress != address(0), "Token must not be zero address");
require(
msg.sender == tokenAddress,
"Token address does not match sender"
);
require(operator == from, "Operator must be the sender");
require(value > 0, "Value must be greater than 0");
require(
payments[id].state == PaymentState.Uninitialized,
"ERC1155 payment must be Uninitialized"
);
require(!isContract(receiver), "Receiver cannot be a contract");

bytes20 paymentHash = ripemd160(
abi.encodePacked(
receiver,
from,
secretHash,
tokenAddress,
tokenId,
value
)
);

payments[id] = Payment(paymentHash, lockTime, PaymentState.PaymentSent);
emit PaymentSent(id);

// Return this magic value to confirm receipt of ERC1155 token
return this.onERC1155Received.selector;
}

function onERC1155BatchReceived(
address, /* operator */
address, /* from */
uint256[] calldata, /* ids */
uint256[] calldata, /* values */
bytes calldata /* data */
) external pure override returns (bytes4) {
revert("Batch transfers not supported");
}

function supportsInterface(bytes4 interfaceId)
public
view
override(ERC165, IERC165)
returns (bool)
{
return
interfaceId == type(IERC1155Receiver).interfaceId ||
super.supportsInterface(interfaceId);
}

function onERC721Received(
address operator,
address from,
uint256 tokenId,
bytes calldata data
) external override returns (bytes4) {
// Decode the data to extract HTLC parameters
(
bytes32 id,
address receiver,
address tokenAddress,
bytes20 secretHash,
uint64 lockTime
) = abi.decode(data, (bytes32, address, address, bytes20, uint64));

require(receiver != address(0), "Receiver must not be zero address");
require(tokenAddress != address(0), "Token must not be zero address");
require(
msg.sender == tokenAddress,
"Token address does not match sender"
);
require(operator == from, "Operator must be the sender");
require(
payments[id].state == PaymentState.Uninitialized,
"ERC721 payment must be Uninitialized"
);
require(!isContract(receiver), "Receiver cannot be a contract");

bytes20 paymentHash = ripemd160(
abi.encodePacked(receiver, from, secretHash, tokenAddress, tokenId)
);

payments[id] = Payment(paymentHash, lockTime, PaymentState.PaymentSent);
emit PaymentSent(id);

// Return this magic value to confirm receipt of ERC721 token
return this.onERC721Received.selector;
}

function isContract(address account) internal view returns (bool) {
uint256 size;
assembly {
size := extcodesize(account)
IERC20(tokenAddress).safeTransfer(msg.sender, amount);
}
return size > 0;
}
}
10 changes: 9 additions & 1 deletion hardhat.config.js
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Original file line number Diff line number Diff line change
@@ -1,7 +1,15 @@
require("@nomicfoundation/hardhat-ethers");

module.exports = {
solidity: "0.8.30",
solidity: {
version: "0.8.33",
settings: {
optimizer: {
enabled: true,
runs: 10000
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@mariocynicys mariocynicys Jan 30, 2026

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Q: what is runs: 10000

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@shamardy shamardy Feb 3, 2026

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The runs parameter tells the optimizer how many times each opcode will execute over the contract's lifetime - it's a trade-off between deployment cost and execution cost.

10000 is a common choice for frequently-used contracts. Higher values have diminishing returns since most inlining decisions are already made.

Ref: Solidity Optimizer Docs

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@shamardy shamardy Feb 3, 2026

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P.S. I favoured execution cost (what the users pay) vs the deployment cost which is what we will pay to deploy the contract.

}
}
},
networks: {
hardhat: {
chainId: 1337, // or another number that Remix will accept
Expand Down
13 changes: 6 additions & 7 deletions package.json
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Original file line number Diff line number Diff line change
@@ -1,22 +1,21 @@
{
"name": "ETOMIC_SWAP",
"version": "1.0.0",
"version": "1.1.0",
"description": "Etomic swap smart contracts and helpers",
"main": "index.js",
"scripts": {
"test": "npx hardhat test"
},
"author": "[email protected]",
"license": "ISC",
"dependencies": {
"chai": "^4.3.10",
"chai-as-promised": "^7.1.1",
"@openzeppelin/contracts": "^5.0.0",
"ripemd160": "^2.0.1"
"@openzeppelin/contracts": "^5.4.0"
},
"devDependencies": {
"hardhat": "^2.22.18",
"@nomicfoundation/hardhat-ethers": "^3.0.8",
"ethers": "^6.10.0"
"ethers": "^6.10.0",
"chai": "^4.3.10",
"chai-as-promised": "^7.1.1",
"ripemd160": "^2.0.3"
}
}
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